Hello All

Been researching my Birney’s for a while now, but something evades me!
My Great Grandfather, Francis Birney was born in 1850 in Dun Laoghaire, County Dublin, the Son of John Birney and Mary Duffy.
Francis was employed in Dun Laoghaire Harbour as a “Pilot”. He married Mary Grantham in St Michael's RC Church, Dun Laoghaire in 1878. Francis and Mary then had eight children:
1.John Joseph BIRNEY b. 1879. d. 1937. John was my Grandfather. Born in Dun Laoghaire.
2.William Wilfred BIRNEY b.1880 d. 1883. Born in Dun Laoghaire.
3.Mary Jane BIRNEY b. 1882, d.1884. Born in Dun Laoghaire.
4.Ellen BIRNEY b. 1883, death unknown. Born in Dun Laoghaire.
5.Teresa Mary BIRNEY b. 1885, d. 1887. Born in Dun Laoghaire.
6.Francis Joseph BIRNEY b. 1886, d. 1941. Born in Dun Laoghaire.
7.Constance BIRNEY b. 1888, death unknown. Born in Dublin.
8.William BIRNEY b. 1892, d. 1918 (WW1). Born in Dublin.
Francis’s Wife, Mary Grantham died after the birth of William, although I have not found here death record as yet.
Now, here’s where it get’s interesting as Francis appears on the 1901 Dublin census with a new Wife named Lucy. They resided at 20 Lr. Oriel Street (North Dock, Dublin). Lucy place od birth is stated as Galbally, Co Tipperary. Lucy is 25 and Francis is 44. They appear again on the 1911 Dublin census living in Church Rd, North Dock, and the census form states they have been married 14 years which would make their year of marriage to be 1896.
Francis and Lucy then had six children.
1.Annie BIRNEY b.1898, death unknown. Born in Dublin.
2.Elizabeth BIRNEY b.1901, death unknown. Born in Dublin.
3.George Joseph BIRNEY b. 1902, death unknown. Born in Dublin.
4.Agatha Margaret BIRNEY b. 1905, death unknown. Born in Dublin.
5.Leo Francis BIRNEY b. 1906, emigrated to USA 1926, death unknown.
6.Veronica Mary BIRNEY b. 1911, death unknown. Born in Dublin.
Francis died 1926 in Grangegorman Hospital, Dublin. Lucy died in 1955 in Dublin.
Lucy Birney was living at 31 Tolka Road, Drumcondra, Dublin, in the Dublin City Electoral Rolls 1939-40.
What I cannot understand is why I cannot find the marriage of Francis and Lucy……..unless they never married!
Any help would be greatly appreciated:)
Kind Regards
David Birney
Victoria, Australia.